This invention relates to curtain wall structures, and more particularly to four corner joints formed between modular frame assemblies wherein a weather tight seal is assured.
Curtain wall structures are known which employ modular frame assemblies arranged in side-by-side interlocked relation and top-to-bottom interlocked relation.
In one such system there is an opening at the location where four frame assemblies meet, through which wind driven rain could enter the building. A sealant block is provided which preferably comprises a sealant impregnated foam material sold under the tradename EMSEAL, and available from Emseal Corporation of Mississuaga, Ontario, Canada. The sealant block receives silicone caulking and is then installed over the opening in the lower modular frame assemblies and prior to the installation of the upper modular frame assemblies. On installation of the upper modular frame assemblies, the sealant block is compressed and seals the opening.
This system has several disadvantages, the most serious being the disintegration of the sealant block over an extended period of time with the result that sooner or later water penetrates into the building. During winter installations, the sealant block cools significantly and becomes rigid so that it cannot be compressed as required and a seal is not formed. In addition, the sealant block with the applied silicone caulking, impairs the drainage of the curtain wall system resulting in moisture penetration into the building.